Indoor location-based services (LBS) including Wi-Fi fingerprinting is a growing field. There are typically two phases in fingerprint-based localization, namely offline site survey and online location query. In the offline phase, a site survey is conducted to collect the fingerprints at known physical locations called reference points (RPs). Each fingerprint is a vector of received signal strength (RSS) values from Wi-Fi access points (APs). The RSS values and their associated locations are then stored in a fingerprint database. In the online phase, a mobile client (target) measures the RSS values at its location. Upon receiving the client measurement, the server matches it with its database to return the client location.
The accuracy of fingerprinting depends on how close the fingerprint database matches with the current signal environment. However, AP signals can change over time due to unexpected AP movement, power adjustment, introduction or removal of wall partitioning, wearing, etc. If such signal change is not reflected in the fingerprint database, localization accuracy would be adversely affected.
The above-described background relating to a Wi-Fi fingerprinting is merely intended to provide a contextual overview of some current issues, and is not intended to be exhaustive. Other contextual information may become further apparent upon review of the following detailed description.